Finger ring stretcher



June l0, 19.152v E G, HENRY 2,600,163

FINGER RING STRETCHER Filed Sept. 25, 1946 Patented June 10, i952 EarleG. Henry, Wilmette,.lll.

Application September 25, 1946, SerialNo. 699,211

2 Claims.

In-the past, finger ring stretchers have been made consisting of arounded, tapered, collapsible and expansible, hardened metal arbor, anoperating handle and Vother auxiliary features. In operation,- the arborwas collapsed to its minimum sizeby movement of the handle in onedirection, the ring to be stretched was slipped along the -tapered arborto such a position that it fitted closely thereon, whereupon. movementof the handle in .the opposite` direction would forcibly expand thearbor and the ring likewise,` stretching Vthe metalof the latter. Incase one stroke of the handle wasinsucient to stretch the ring therequiredamount, the operation could be repeated as often asnecessary,for each time the ring was stretchedV itcould beslipped farther alongthe tapered arbor and be expanded to increasingly larger diameters onsuccessive strokes. While some ring stretchers of this general type havebeen made which would do the work satisfactorily, none of them have beencommercially successfulfchiefly becausethe actual mechanisms havebeen-excessivelyinconvenient to set up and operate, and diiicult andexpensive to produce.

The principal object of the present invention is to provide -a Yringstretcher, of the general type described above, but having a novelgeneral'` arrangementv and novel features which permit the device v tobe constructed' from relatively few parts, all 'simple and inexpensiveto produce, and the device as a whole to-be light in weight, simple toassemble and dis-assemble, and efcient in operation.

I attain the aforesaid object by means ofthe improvedv constructionillustrated in the accompanying drawing, in whichs- Figure 1 is a sideview of a-nger ring stretcher embodying the present invention in itspreferredlform, with the parts in their normal,- idle position and theoperating lever shown in kbroken lines atthe end of an arbor-expandingvstroke; Fig. 2 is a section on line 22 of Fig. 1,-the upper part of thelink that serves as 'a fulcrum'for thelever being broken away, showingthe arbor expanded as it is when the lever is down; Fig.v 3 is a topplan view of the device-appearing in Figs. 1 and 2; Fig. 4 is atransverse section throughthe sleeve-like arbor blank,A onv a muchlarger scale, needing only to be divided into four segments to become anished arbor; Fig. 5 is a section on line 5-5 of Fig. l through thearbor closed on the stem by which it isexpanded, showing theA foursegments in edge contact with each other, the scale being the same as inFig. 4;*Figs. 6 and 7 are cross sections on lines S-I-and 'I-JI of' Fig.2, respectively, but on a larger scale; Fig. 8 is a perspective View ofthe split spring ring or clip that holds the lower ends of thearborsections ina'yielding grip; Fig. 9' is a perspective View of thesplit spring ring or clip at the other end of the arbor.

Referring to theV drawing, in` detail, II isv a channel-shaped piece ofrelatively thin sheetmetal, which'formsthe principalfstructural elementof the base lof the device.y Partially enclosed and concealed -bythechannel II, :andcemented into position therein', isa wooden ller I2,

to the bottom surface'ofwhich-a 'sheet of felt I3 wood ller being outaway, as vat I2a, to'makeiroom for member'lll. I5"is`a round, tapered,

metal stem,A rigidly 'attachedi'to baseparts I I andy I4 by meansV ofthe' nut I6. I1 is a U-shaped part, or fork, made of relativelythick'sheet metal and rigidly welded or riveted at its closed end tobase parts 'I I and III- I8 is a link, pivotally connected'at one end tothe' fork I1,.by means of'a pin I9'. 20' is a lever, formed fromrelatively thick sheet metal' and'pivotally connected to the upper endof link I 8 by means of a pin 2 I that is parallel'to pin' I 9.

22 is' a rounded, tapered,V metal arbor consisting of the fourvseparatesegments, 24, 25' and 26. Segments 23 and 24 arepivotally'connecte'd to the lever 20 by means of'a pin 2l. which tswithin round, transverse holes in segments 23 and 26, preventingrelative vertical dis'- placement of these two segments. 29 is a similarpin which similarly prevents relative Verticaldisplacement of segments24 and 25. Hence the arbor always moves vertically as a unit. Pin 21 isat right angles to one of the two planes along which the arbor isdivided, while pins 28 and v29 are at right angles to the other of suchplanes;A and so the lateral movements of each segment can only be atright angles to one of these planes while paralleling the other.

30 is a clip in the form of a C-shaped springsteel collar or split ringwhich lits within a groove 22a near the upper end of arbor 22 and tendsto squeeze the latter toward its collapsed or minimum size. 3l is asimilar but larger collaror split ring ywhich nts within a similargroove -22b 28`is a pinl near the lower end of the arbor and tends tocollapse the latter. 32 is a coil spring which fits loosely around thelower, cylindrical portion I5a of Stem I5 and presses upward against thebottom surface of arbor 22, tending to lift the arbor into its upper orcollapsed position.

When the ring stretcher is standing in its normal or idle position,spring 32 is holding arbor 22 at the upper end of its stroke, springcollars 30 and 3| are holding the arbor in its collapsed condition, andthe outer or handle end of lever 20 is tilted upward, as shown in fulllines in Fig. 1. When a finger ring of relatively small diameter ispassed over the top end of the arbor and allowed to drop, it will cometo rest in contact with the periphery of the arbor and relatively nearto the top. A larger ring will drop farther down on the arbor beforecoming to rest. Then, when the lever is pushed forcibly downward, for afull stroke, into its lowest position, as shown in broken lines in Fig.l, the arbor is forced downward and expanded to its maximum size by thewedging action of the tapered stem I5; thereby stretching the ring by adefinite, small amount, compressing spring 32 and expanding the springcollars 30 and 3I. In some cases, only a fraction of a full stroke maybe required to stretch the ring sufficiently, while in other cases oneor more additional full or fractional strokes may be required.

Finger rings which have local weaknesses, as is A the case with manyrings designed for holding large gems, cannot, of course, be safelystretched on this type of stretcher, since such a ring would break atthe weak place before stretching of the remainder of the circumferencecould occur.

The range of swinging movements of lever 20 is small, preferably notmore than twenty degrees, half above and half below a horizontal plane.Consequently, when operating the device, the force which the hand of theoperator exerts on the lever acts almost entirely in a downwarddirection, so that maximum force may be exerted Without any tendency tocause the device to slide along the surface on which its base may beresting. thrust of the lever is transmitted to the base a short distancefrom one end of the latter, while the base extends many times thatdistance underneath the long arm of the lever, the device cannot tiltwhen the lever is pressed down. Consequently, it is unnecessary toprovide means for clamping this ring stretcher to some rigid, stationaryobject, as is the case with some other ring stretchers of this generaltype which have been made; and my ring stretcher, unlike these others,may at any time be instantly picked up and moved from place to place andmay be operated on any firm, approximately horizontal surface.

For stability, the base of my device is made relatively wide, but byusing the sheet-metal channel II, combined with the wooden filler I2,the desired width and rigidity are secured without making the baseunduly heavy. Moreover, this sheet-metal channel is wellY adapted forreceiving a handsome, economical and durable finish, such as plating orenamel.

The sheet-metal, channel-shaped lever 20 is not only strong and lightand adapted for economical production and finishing, but its variousfeatures are peculiarly adapted for efficiently performing their variousfunctions. The handle end is broad and comfortable for receivingdownward pressure from the palm of the hand. The two side flanges 20aand 20h, of the lever, one on each Furthermore, because the downward tside of the arbor 22, and through which the pin 21 extends, pressdownward on both ends of the pin, minimizing the tendency to bend ortilt the pin. The fulcrum of the lever is located at the two widelyseparated ends of the pin 2I, which also extends through iianges 20a and20h, so that undesirable movements of the lever, sideways or angularlyabout its longitudinal axis, are minimized. This smooth, controlledmovement is of great help in stretching valuable rings, where one mustjudge by the sense of touch how much force it is safe to apply withoutcracking the ring.

The three pins 21, 28 and 29 maintain the four segments 23, 24, 25 and26 of the arbor in a fixed vertical relationship but allow freehorizontal movements of the segments toward and from each other, withthe meeting edge faces at all times parallel to each other. Moreover,since the three pins prevent mutual rotational movements of the foursegments about their vertical axes, and since the segments are pressedinto rm contact with the round, central stem I5, by the spring'collars30 and 3l, during all stages of normal operation of the device, the foursegments at all times remain uniformly distributed circumferentiallyaround the stem. That is, the four longitudinal gaps between thesegments remain equal to each other at all stages, from completecollapse of the arbor, when the gaps close up completely, to maximumexpansion. Without this circumferential control, all four of thesegments, when the arbor was fully expanded, might be crowded together,so that three of the gaps would practically disappear while theremaining gap would be so wide as to produce a definitely flat place ononce side of the ring.

Pin I9 is a tight press fit in the two holes in the fork I1, or isotherwise held immovable therein, and is a freely turning t in link I8,where the length of the hole provides ample bearing surface. Similarly,pin 2l is xed relative to lever 20 and is a freely turning fit in thehole in link I8, where the bearing surface is ample. Pin 21, likewise,is xed relative to lever 20 and is a freely turning and sliding t in thetwo holes in Segments 23 and 24, which provide ample bearing surfaces.Pin 28 is xed with respect to segment 23, but slides freely in the holein segment 26. Similarly, pin 29 is immovable relative to segment 24 andslides freely in the hole in segment 25.

All of the joints between the parts which consist of the five small,round pins I9, 2l, 21, 28 and 29, together with the holes into whichthey fit, are not only extremely economical to produce, relative toother forms of suitable joints, but they reduce lost motion and frictionto a minimum, so that the hand of the operator can feel the stretchingof the metal of the ring with the least possible distraction, almost asif his hand were in direct contact with the ring itself.

In some other ring stretchers of the general type under discussion, aswell as in some other devices in which expanding arbors areincorporated, the split arbor is supported and restrained againstendwise motion by the fixed framework of the device, while a separate,internal, wedgelike part is forced endwise between the segments of thesplit arbor so as to spread them apart. In my invention, by contrast,the central wedge also serves as the sole support and vertical guide forthe split arbor. One simple, stationary part, the stem I5, performs allthree of these important functions, supporting, guiding and wedging.Both of the necessary motions; endwise-and-radial (or expansional), are,in my device', imparted to the ring stretcher which require'sany buttli'e-Jno'std ordinary toolsland-processes-:fo'riitsmanufacture.Theiouter-surface'of-this arbor'f-m-ust bef'exceptionallyhardandAdurable solasl to1withstand :the severe local pressure strains to whichit is subjected during the stretching of rings, and not become groovedor roughened thereby.

By far the most suitable material for this arbor, especially from thestandpoint of economy, is steel which has been hardened by heattreatment, although other materials or combinations of materials whichwould function satisfactorily could no doubt -be found, Unfortunately,any such heat treatment tends to warp steel parts, espe-I cially whenthey are relatively long and thin and non-symmetrical in cross section,as are the arbor segments 23, 24, 25 and 26. To serve their purposeProperly, these segments must be reasonably straight. Assume, forinstance, that one of the segments is slightly bowed, so that it comesinto contact with the central stem I 5 only near its two ends, leaving.a space between the segment and the stem along the middle portion ofthe arbor, and that a medium sized ring is dropped onto the arbor andcomes to rest in contact with the arbor segments opposite the placewhere one of the segments fails to make proper contact with the stem l5.Then, when the lever is depressed, so as to expand the arbor, the bowedsegment will yield elastically to the pressure and be straightened outagainst the side of the stem, after which the normal stretching actionagainst the ring begins to occur. This lost motion, due to the yieldingof the bowed segment, would not only Waste a part of the stroke, but thehand of the operator would `be unable to feel sensitively how much forcewas being applied to the ring.

In some cases, similar steel parts which have thus become warped duringtheir heat-treatment, have been straightened by mechanical means, butsuch processes are, at best, slow and uncertain. When similarheat-treated steel parts are used in devices such ,as precision tools,where the parts must be finished to a very high degree of accuracy, itis customary to grind all critical surfaces after the heat treatment.Such grinding operations for the tapered arbor segments 23, 24, and 26,particularly for the conical inner surfaces of these parts, would beprohibitively expensive in the case of a ring stretcher to be sold inlarge numbers at a low price.

To avoid these diculties in the manufacture of these arbor segments, Iproceed as follows: Beginning with a square steel bar having the samecross sectional size as the square portion of the complete arbor 22which fits between the two vertical anges of the lever 20, I rst drilland ream the three transverse holes into which the pins 2l, 28 and 29are later fitted; drill and ream the longitudinal, perform the variousexternal turning operations; and as a final machining operation, asshown in Fig. 4, cut four narrow, longitudinal slots 33, 33 which almostbut not quite separate the arbor into its four segments, the latterbeing still joined to each other by thin bridges of metal 34, 34,extending from end to end of the arbor.

The next step in the manufacture of the arbor tapered, central hole;

is'a L the hardening yi-:hear

getlier, frestrain eaclrio'ther from-warping. i Afterundergoing-exposure ltoi an lextremely' low tem'- I perature,Lwhich!relievesllocal tensionsfin the steel, 'set-1 upf-by"l theohardening vtreatment, the fourvse'gmentsare Icracked1apartandffthe1rough ed'gesgrepresentinglthe i-teinporarybridgesl 34,-"

34, are1lremovedibyfa `quick, simple-'grinding operation-.1The-slight-fresidual warpage resulting from this method of treatment isnegligible.

It is desirable-that the width of the slots 33. 33o' be equal to"-y themaximum-:diametricalf expansion of the arbor. At stroke, when the arboris fully collapsed, it is not truly circular in cross section; each twoadjacent, curved, outer surfaces meet at a slight angle, as best seen inFig. 5. At the termination of the stroke, when the arbor has beenexpanded to its maximum size, it has assumed as nearly as possible atruly circular form in cross section, as best seen in Fig. 4, whichdesirable shape is shared by any ring which has just been stretched.

In order to make clear this diil'erence in shape under the twoconditions, the width of the slot, as indicated in Figure 4, and theequivalent magnitude of the collapsing movement, as indicated in Fig. 5,have been greatly exaggerated; in actuality, the slots are hardly wideenough to produce any perceptible deviation from a truly circular formeven when the arbor is fully collapsed. It is nevertheless desirablethat the maximum deviation from a truly circular form occur when thearbor is collapsed, instead of when it is fully expanded, at which timeit impresses its shape on the rings.

While I have illustrated and described with particularity only the oneembodiment of each novel feature of my invention, I do not desire to belimited to the exact structural details thus illustrated and described;but intend to cover all forms and arrangements that come within thedefinitions of the invention constituting the appended claims.

I claim:

l. A nger ring stretcher comprising a base, a stationary tapered stemrising from the base, an expansible tapered arbor surrounding the stemand divided lengthwise into four equal segments, spring means on thearbor to cause the arbor to be yieldingly held in a contractedcondition, a pin extending transversely through two segments of thearbor toward the lower end, at right angles to the plane of divisionbetween the latter segments, and having a sliding fit in at least one ofsuch segments, an operating lever having portions lying on oppositesides of the lower end of the arbor and lixed to the ends of theaforesaid pin, and two additional pins on opposite sides of and parallel to said plane, each of the latter pins passing through the twoarbor segments on the corresponding side of said plane and beingslidable in at least one of the latter segments.

2. A finger ring stretcher comprising a base, a stationary tapered stemmounted on and rising from the base, an expansible tapered arborsurrounding and slidable lengthwise of the stem, a l

long, wide lever containing near one end a large opening through whichthe arbor freely extends, an upright link hinged to the base below thesaid end of the lever, a hingeconnection between the upper end of thelink and the lever, a hinge pin extending through two of the segthe;'beginning of i the`y ments at the lower end of the arbor and xed' atits ends to the lever atopposite sides ofthe opening in the latter, theaxis of said pinbeing parallel to the axes of the hinges at the two endsoi* the link, and additional pins each passing transversely through twoarbor segments `and slidable in at least one of the latter to form withthe hinge pin tie means to hold the arbor segments against relativelengthwise movements.,

EARLE G. HENRY.

REFERENCES CITED The following references are of record in the iile ofthis patent:

8 UNITED STATES PATENTS Number Number Name Date Hughes May 31, 1927Pratt June 9, 1942 FOREIGN PATENTS Country Date Germany Aug. 29, 1900Germany Dec. 14, 1901 Germany May 28, 1926

